Design Principles

The principle of ultraviolet sterilization in urban small-scale domestic sewage treatment equipment is to use the energy of ultraviolet light to destroy the DNA of various viruses, bacteria, and other pathogenic bodies in the water. Ultraviolet light penetrates the cell membrane and nucleus of microorganisms, destroys the molecular bonds of nucleic acids, and causes them to lose their replication ability or activity and die. The ultraviolet sterilization band is between 200-300nm, with the 253.7nm band having the strongest ability.

Small scale urban domestic sewage treatment equipment and ultraviolet disinfection technology have the advantages of safety, efficiency, low cost, and no production of by-products. After UV disinfection, there is no secondary pollution or by-products, and the effluent can be reused for irrigation in farmland, forest land, or underground water injection, achieving resource utilization.

Design Basis

2.1 Disinfection standard: The fecal coliforms in the effluent should not exceed 1 × 103 MPN/L (Grade A standard); The fecal coliforms in the effluent should not exceed 1 × 104 MPN/L (Grade I B standard) (30 day geometric mean).

2.2 UV dose: At peak flow rate and UV transmittance of 65%, the effective UV dose that the system can achieve at the end of the lamp life, that is, the biological verification dose of the sterilizer should not be less than 20000 µ Ws/cm2 according to the first level A standard, and not less than 16000 µ Ws/cm2 according to the first level B standard.

Composition of equipment

The open channel ultraviolet system consists of four main parts: ultraviolet disinfection module, control system, effluent system, and cleaning system.

Each standardized ultraviolet disinfection module consists of a stainless steel lamp holder, ultraviolet lamp tube, quartz sleeve, and cleaning structure. The entire ultraviolet disinfection system is composed of several ultraviolet disinfection modules, which are easy to install, operate, and maintain.

Application Range

Mainly used in small-scale sewage treatment plants, township sewage treatment plants, sewage disinfection and reuse disinfection, etc.